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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2008 Oracle. All rights reserved.
4 */
5
6#ifndef BTRFS_COMPRESSION_H
7#define BTRFS_COMPRESSION_H
8
9#include <linux/sizes.h>
10
11struct btrfs_inode;
12
13/*
14 * We want to make sure that amount of RAM required to uncompress an extent is
15 * reasonable, so we limit the total size in ram of a compressed extent to
16 * 128k. This is a crucial number because it also controls how easily we can
17 * spread reads across cpus for decompression.
18 *
19 * We also want to make sure the amount of IO required to do a random read is
20 * reasonably small, so we limit the size of a compressed extent to 128k.
21 */
22
23/* Maximum length of compressed data stored on disk */
24#define BTRFS_MAX_COMPRESSED (SZ_128K)
25/* Maximum size of data before compression */
26#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
27
28#define BTRFS_ZLIB_DEFAULT_LEVEL 3
29
30struct compressed_bio {
31 /* number of bios pending for this compressed extent */
32 refcount_t pending_bios;
33
34 /* the pages with the compressed data on them */
35 struct page **compressed_pages;
36
37 /* inode that owns this data */
38 struct inode *inode;
39
40 /* starting offset in the inode for our pages */
41 u64 start;
42
43 /* number of bytes in the inode we're working on */
44 unsigned long len;
45
46 /* number of bytes on disk */
47 unsigned long compressed_len;
48
49 /* the compression algorithm for this bio */
50 int compress_type;
51
52 /* number of compressed pages in the array */
53 unsigned long nr_pages;
54
55 /* IO errors */
56 int errors;
57 int mirror_num;
58
59 /* for reads, this is the bio we are copying the data into */
60 struct bio *orig_bio;
61
62 /*
63 * the start of a variable length array of checksums only
64 * used by reads
65 */
66 u8 sums[];
67};
68
69static inline unsigned int btrfs_compress_type(unsigned int type_level)
70{
71 return (type_level & 0xF);
72}
73
74static inline unsigned int btrfs_compress_level(unsigned int type_level)
75{
76 return ((type_level & 0xF0) >> 4);
77}
78
79void __init btrfs_init_compress(void);
80void __cold btrfs_exit_compress(void);
81
82int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
83 u64 start, struct page **pages,
84 unsigned long *out_pages,
85 unsigned long *total_in,
86 unsigned long *total_out);
87int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
88 unsigned long start_byte, size_t srclen, size_t destlen);
89int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start,
90 unsigned long total_out, u64 disk_start,
91 struct bio *bio);
92
93blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
94 unsigned long len, u64 disk_start,
95 unsigned long compressed_len,
96 struct page **compressed_pages,
97 unsigned long nr_pages,
98 unsigned int write_flags,
99 struct cgroup_subsys_state *blkcg_css);
100blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
101 int mirror_num, unsigned long bio_flags);
102
103unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
104
105enum btrfs_compression_type {
106 BTRFS_COMPRESS_NONE = 0,
107 BTRFS_COMPRESS_ZLIB = 1,
108 BTRFS_COMPRESS_LZO = 2,
109 BTRFS_COMPRESS_ZSTD = 3,
110 BTRFS_NR_COMPRESS_TYPES = 4,
111};
112
113struct workspace_manager {
114 struct list_head idle_ws;
115 spinlock_t ws_lock;
116 /* Number of free workspaces */
117 int free_ws;
118 /* Total number of allocated workspaces */
119 atomic_t total_ws;
120 /* Waiters for a free workspace */
121 wait_queue_head_t ws_wait;
122};
123
124struct list_head *btrfs_get_workspace(int type, unsigned int level);
125void btrfs_put_workspace(int type, struct list_head *ws);
126
127struct btrfs_compress_op {
128 struct workspace_manager *workspace_manager;
129 /* Maximum level supported by the compression algorithm */
130 unsigned int max_level;
131 unsigned int default_level;
132};
133
134/* The heuristic workspaces are managed via the 0th workspace manager */
135#define BTRFS_NR_WORKSPACE_MANAGERS BTRFS_NR_COMPRESS_TYPES
136
137extern const struct btrfs_compress_op btrfs_heuristic_compress;
138extern const struct btrfs_compress_op btrfs_zlib_compress;
139extern const struct btrfs_compress_op btrfs_lzo_compress;
140extern const struct btrfs_compress_op btrfs_zstd_compress;
141
142const char* btrfs_compress_type2str(enum btrfs_compression_type type);
143bool btrfs_compress_is_valid_type(const char *str, size_t len);
144
145int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end);
146
147#endif